Why does wordpress need the cookies to be activated to login?

Everytime my users try to login, they get the error message saying that wordpress needs the cookies to be activated in there browser to login. I activated them home and it fixed problem, but I can’t explain to every single user how to do it and, at some places they have them blocked and you can change the settings like in the libraries so it is really frustrating for my users.

I was wondering if there was not a way to disable this so the cookies don’t have to be activated?

Thanks, De3r7! ??